The inventive concepts relate to semiconductor devices and methods of manufacturing the same. More particularly, the inventive concepts relate to non-volatile semiconductor memory devices and methods of manufacturing the same.
The integration density of semiconductor memory devices may be proportional to the cost of the semiconductor memory devices. A conventional two-dimensional (2D) memory device includes a planar array of unit memory cells formed of fine patterns of certain elements and features. The integration density of such a conventional two-dimensional (2D) memory device mainly corresponds to the area occupied by a unit memory cell of the device. Thus, the degree to which the integration density of a 2D memory device can be increased greatly depends on advances in techniques of forming fine patterns. However, apparatuses for forming fine patterns are very expensive to begin with and the cost of these apparatuses will only increase along with the fineness of the patterns that they are able to produce. Therefore, manufacturing costs may impose limits on the extent to which the integration densities of 2D memory devices are increased. In light of this, three-dimensional (3D) semiconductor devices have been developed. Three-dimensional (3D) semiconductor memory devices provide high integration densities and excellent performance while being relative inexpensive to manufacture per unit memory cell.